Gregorij Kurillo, Jay J. Han, Richard T. Abresch, Alina Nicorici, Posu Van and Ruzena Bajcsy have published the article “Development and Application of Stereo Camera-Based Upper Extremity Workspace Evaluation in Patients with Neuromuscular Diseases” on PLOSONE (Volume 7, Issue 9, e45341, www.plosone.org) (17 Sep. 2012), disclosing a stereo camera-based reachable workspace analysis system which is capable of distinguishing individuals with varying degrees of proximal upper limb functional impairments. Prescribed movements are performed along a workspace envelope. The user is guided by a therapist on what movements to do. The results are used to derive sphere segments as a model-based assumption. The disclosed stereo camera-based reachable workspace acquisition system combined with customized 3D workspace analysis algorithm was compared against a sub-millimeter motion capture system. The stereo camera-based system was robust, with minimal loss of data points, and with the average hand trajectory error of about 40 mm, which resulted to about 5% error of the total arm distance. For a number of persons, the workspace envelope surface areas generated from the 3D hand trajectory captured by the stereo camera were compared. Normalization of acquired reachable workspace surface areas to the surface area of the unit hemi-sphere allowed comparison between subjects. The healthy group's relative surface areas were about 0.618 and 0.552, for the right and left arm, respectively, while the surface areas for the individuals with neuromuscular diseases ranged from 0.03 and 0.09 (the most severely affected individual) to 0.62 and 0.50 (very mildly affected individual), for the right and left arm, respectively. Neuromuscular patients with severe arm weakness demonstrated movement largely limited to the ipsilateral lower quadrant of their reachable workspace.
The findings indicate that the proposed stereo camera-based reachable workspace analysis system is capable of distinguishing individuals with varying degrees of proximal upper limb functional impairments. The method to intuitively display and effectively analyze reachable workspace complements traditional upper limb functional assessments and allows quantifying and monitoring upper limb functions.
Claudia Rudhe, Urs Albisser, Michelle L Starkey, Armin Curt and Marc Bolliger have published the article “Reliability of movement workspace measurements in a passive arm orthosis used in spinal cord injury rehabilitation” in Journal of NeuroEngineering and Rehabilitation 2012, 9; 37 (http://www.jneuroengrehab.com/) (9 Jun. 2012). The arm of the user is moved to specific points in the reachable workspace to calibrate a model that approximates the workspace geometry (box, ellipsoid, etc.). As robotic and non-robotic training devices are increasingly being used in the rehabilitation of upper limb function in subjects with neurological disorders, the article provides an evaluation of the reliability of movement measures as assessed with an ArmeoSpring system (provided by Hocoma AG, Switzerland) for the application to the rehabilitation of patients suffering from cervical spinal cord injury (SCI).
Reliability (intra- and inter-rater reliability) of the movement workspace (representing multiple ranges of movement) and the influence of varying seating conditions (5 different chair conditions) was assessed in twenty control subjects. In eight patients with cervical SCI the test-retest reliability (tested twice on the same day by the same rater) was assessed as well as a correlation of the movement workspace to retrieve self-care items as scored by the spinal cord independence measure (SCIM 3). Although the used movement workspace in the tested device has the shape of a cube instead of the anatomical spherical shape the findings were found to be related to clinical outcomes. The workspace volume was calculated from the data provided by the Armeo device and be followed over time to document changes during the course of rehabilitation.
The movement workspace is a multiple joint measure and does not assess the maximal shoulder movement capacity in a single direction as assessed in a single joint range-of-motion measurement. However, the reliability information from this more functional movement seems to be very good compared to, for example, single joint goniometry measurements of the shoulder. Reliability studies for goniometry measurements in the shoulder have a large intra- and inter-rater variability in results.
Klopcar N, Tomsic M and Lenarcic J have published the article “A kinematic model of the shoulder complex to evaluate the arm-reachable workspace.” in J Biomech 2005, 40:86-91, disclosing computing a reachable workspace of the arm movement of a user. Klopcar N and Lenarcic J have also published the article “Kinematic Model for Determination of Human Arm Reachable Workspace” in Meccanica (2005) 40:203-219. Said article discloses, especially in its FIGS. 10 and 11 and the relating description, the computed reachable workspace of the arm movement of a user.
A general training apparatus and corresponding method performed using such a training apparatus can be found in EP 2 660 742 from the applicant, inter alia used as means of support to provide for physiotherapy of the back of a person Further similar devices are disclosed in US 2013/171601 and WO2011/004403.